Clamping bodies in the form of a screw connection are used, for example, in electrical connecting terminals such as terminal blocks or lustre terminals. Electrical connecting terminals with screw connections are characterised by their high clamping forces, which are transferable to electrical conductors consistently for years. With this type of terminal, predetermined high clamping forces can be maintained without fluctuations, even with vibrations acting on the electrical connecting terminal. Due to these characteristics, electrical connecting terminals with screw connections are also used as a preference in high-performance industrial applications with moving and vibrating machine components.
To construct an electrical connecting terminal, the clamping body is normally arranged inside a housing made of insulating material. The clamping body pocket of the clamping body can be constructed from an electrically conductive material. A threaded bore, into which a screw is inserted and which is guided as far as the inside of the receiving space of the clamping body, is formed on a side wall of the clamping body pocket. The screw head of the screw is accessible via an opening provided in the housing made of insulating material such that the screw can be turned with its tip into the receiving space and can clamp an electrical conductor that has been inserted here. It is, however, also possible that when the screw is turned, the screw pulls the clamping body upwards and pushes the conductor against a current bar such that no direct contact occurs between conductor and screw.
The clamping body pocket can be produced from a curved strip-shaped sheet metal element, which is curved or folded according to the contour of the clamping body pocket. Furthermore, the clamping body pocket can be produced from a solid profile, which is processed accordingly by machining processes, such as sawing, drilling, milling, broaching or thread cutting, for example, in order to obtain the form of the clamping body pocket. In contrast to a clamping body pocket produced from a curved strip-shaped sheet metal element, the clamping body pocket produced from a solid profile has a more consistent outer contour, since no folding or bending points have to be provided. Moreover, a clamping body pocket produced from a solid profile can be constructed with smaller dimensions than a clamping body pocket produced from a curved strip-shaped sheet metal element, so that the space requirement for the clamping body pocket can be reduced. Moreover, clamping body pockets produced from a solid profile can have a longer threaded bore, as a result of which, by means of the screw inserted into the threaded bore, a higher torque and therefore a higher axial force can be applied to the electrical conductor clamped by the screw. In order to improve the processing, in particular in relation to the machine processing, of the material for producing a clamping body, it is usual to apply lead to the material of the clamping body. This added lead is, however, a disadvantage when compliance with the EU lead-free directive (regulations regarding the restriction of certain hazardous substances in the electrical and electronic industry and end-of-life vehicle regulations) is required.